City a mixture of Paul Cezanne and 35,000 University Students

Mediterranean countries are noted for the beauty and dramatic seasonal changes of their plane trees.

Shorn drastically of all foliage, they become unsightly knobs in winter, sprout tiny leaves of pale green at the onset of spring, then open during summer like nature’s umbrellas into long stands of soothing shade down city boulevards.

This town’s main thoroughfare, broad and majestic Cours Mirabeau, is Southern Europe’s Louvre of plane trees.

Aix, named Aquae Sextiae by the Romans a century before Christ for its abundant water in arid Provence, certainly has its share now.

Handsome fountains mark each end of Mirabeau, several others along the way provide a further cooling scene for patrons of an endless line of sidewalk cafes and residents of handsome 17th-Century town houses bordering the boulevard.

Bustling University Town

Much of Aix’s vitality and carefree nature comes from its 15th-Century university, today’s 35,000 students making up 30% of the population. They keep the town lively and bustling, a substantial mix of foreign students adding the color and manner of their home countries

Perhaps Mirabeau himself was another factor in the city’s tolerant attitude. Already broke, ugly and a notorious ne’er-do-well, the profligate count compromised, boasted of his conquest and then married the town’s richest heiress. He went to prison after spending all her money, emerged to be elected to the Estates General in 1789 and become the French Revolution’s most noted orator.

The second-most famed citizen of Aix was Paul Cezanne, but alas, when he returned from Paris, his paintings did not follow and the city’s meager collection is disappointing at best.

Here to there: Air France flies nonstop from Los Angeles to Paris, and UTA recently began San Francisco-Paris service. Several domestic carriers will get you there without changes, foreign lines with home-country stops. Air Inter flies Paris-Marseilles, or take French National Railroads’ hot TGV at 165 m.p.h. to the port city, then bus the remaining 18 miles inland to Aix.

How long/how much? Aix demands at least two days of anyone’s time, if only in the hopes of picking up a bit of the languorous Provencal life style, another full day for exploring the Luberon hills north of town. We find lodging prices moderate, dining costs depending upon the menu or a la carte selections you choose.

A few fast facts: The franc was recently valued at 5.7 to the dollar. While there is no best time for a visit, most of the year being pleasant with no big rainy season, Provencal summers can be good and hot. Most of the old town is walkable, a city bus for the far reaches.

Getting settled in: St. Christophe (2 Ave. Victor Hugo; $44 double) has a fine location beside the city tourist office at east end of Cours Mirabeau. Inviting lobby with comfortable couches and chairs, paintings of Provence on walls, two sidewalk cafes outside front door. Contemporary bedrooms of moderate size, TVs, large baths.

Le Prieure (Route de Sisteron; $20 to $40 double) is just outside town, part of a former estate set in lovely 17th-Century formal gardens. There’s a sense of quietude in this small chateau that makes you long for an extended stay, which madame prefers. The 30 bedrooms, a few rather small, are all decorated differently in charming styles, original local art in lobby, antiques everywhere, including an enormous 14th-Century water heater of copper. Breakfast only and book reservations early for this one.

Le Manoir (8 rue d’Entrecasteaux; $51 to $69) began as a 14th-Century cloister and still retains an air of solitude and tranquility at mid-city. Enter through a small and flowery courtyard, traditional room decor, take breakfast inside or out under the vaulted ceilings of the original cloister.

A tossup for the town’s best is Des Augustins (3 rue de la Masse) or Cezanne (40 Ave. Victor Hugo), both with double prices in the $63 to $130 range. Each has an aura of bygone eras, the former a converted 12th-Century convent, latter equally nostalgic with period furnishings, faience baths. Both centrally located, either an excellent choice.

Regional food and drink: One of the more interesting Provencal dishes for a venturesome diner is pieds et paquets, little packages of sheep’s trotters and tripe prepared with the region’s aromatic herbs and a great deal of know how. Meals often start with black olives to go with your pastis or kir, the same olives made into tapenade , a spread heavy with garlic and oil and heavenly on toasted rounds of a baguette.

The robust reds and rich and luscious whites of Rhone Valley wines go very well indeed with Provencal dishes, a fine Blanc de Blancs from the coastal town of Cassis being our favorite with seafood. Calisones d’Aix , an almond-flavored petit four, and chocolates de puyricard , both famous throughout Europe, are sold and devoured all over the town.

Moderate-cost dining: Poivre et Sal (9 rue Constantin) has simple and bright contemporary decor with original art on walls, and the imaginative chef has made it one of the town’s best. The feuillete of mussels in a creamed fennel sauce was outstanding, the same for another vol-au-vent of fresh asparagus with Parma ham. Tiny lamb chops grilled with Provencal herbs and rabbit sauteed in white wine and herbs were both main courses to reckon with. Fresh white local cheese ended the meal happily.

Eugenie’s (1 rue Brueys) is a very pretty place, small and intimate with lace curtains, pink tablecloths and napkins, gobs of flowers everywhere. A four-course menu of excellent Provencal selections will cost you about $16.

Abbaye des Cordeliers (21 rue Lieutaud) is downright beautiful, its vaulted ceilings and garden tables a cool and inviting spot for lunch or dinner. A house specialty is lapereau aux cepes , young rabbit sauteed with wild mushrooms, a traditional dish of Provence.

Le Comte d’Aix (17 rue de la Couronne) is another small one with rustic furnishings, beamed ceilings and, again, lots of flowers. You’ll get a menu here for about $12.75: pate or mussels; navarin d’agneau , a lamb stew with tomatoes, potatoes, onions and herbs; a selection of chevres . Other menus are pricier.

On your own: First, get the feel of the town with a stroll down Cours Mirabeau, pausing for a coffee or aperitif at Cafe Le Mazarin or Le Deux Garcons, both heady studies in fin de siecle furnishings and atmosphere. Then visit the Granet Museum for such Cezannes as the city has, making sure to see the nearby Four Dolphin Fountain, a real charmer spouting water since the 17th Century. The cathedral is a mixed bag of Romanesque-Gothic styles, its adjoining cloister pure Romanesque and a lovely retreat.

It’s impossible to visit all of the enchanting perched villages of the Luberon hills, but try to drive through as many as possible in your allotted time. Bonnieux, Lourmarin with its 15th-Century chateau and Lacoste, once the home of the infamous Marquis de Sade, are three of the most fetching. The Luberon, or indeed any part of Provence, offers the perfect spot for a picnic around every curve. And each little town seems to have its local cheese, salami and wine, so pick up your lunch along the way.

For more information: Call the French Government Tourist Office at (213) 271-6665 or 272-2661, or write (9401 Wilshire Blvd., Suite 840, Beverly Hills 90212) for a brochure on Provence, a map of the region and listing of hotels. Ask for the Aix package.